Today I sandblasted the head of my spare engine. I pulled this engine out of a car that I paid $200 to salvage anything but the suspension parts, so I was not expecting a perfect engine. It has the usual cracks between bores. The head shows significant erosion on cylinder three extending to areas around the valve seat.
Some opinions please, How does this happen? Head gasket failure due to the cracking? And is this head useless?
Thanks

 

Hmm, I wouldn't say its scrap yet. Those pits could be smoothed out a bit, and then the head skimmed. If the block has the usual cracks between the bores, the only real cure is fitting of top-hat (aka lipped) liners, an expensive job. The lips on the liners cover the cracks

 

I agree.

I have had that on some, and it has not caused any issues, unlike the big brother V12.

That seat insert is possible still very sound, but any half decent engine repair shop could confirm that in a second.

Possible some erosion from water sitting in that cylinder for years.

The water ways are very good, so I reckon the head is OK.

At worst, a new valve seat, maybe. Then skim it for flatness.

 

I wouldnt use that head. The chamber is no longer smooth and that could cause combustion problem like pre-ignition. Carbon hot spots will build up the pits. The pits around the seats clearly visible and there no telling how deep those pit go under and around the seat. How could you trust it to not drop that seat? You may end up with a big machinist bill only to find out the head is not safe to use. If this was a high dollar exotic head a welder could repair it and then metal finish the filler welds but it's a XK head and they can be found in far better shape than this.